Ammonium Sulfate Crystals Research Articles

A bioinspired doxorubicin-carried albumin Nanocage against aggressive Cancer via systemic targeting of tumor and lymph node metastasis

Cancer metastasis and recurrence are obstacles to successful treatment of aggressive cancer. To address this challenge, chemotherapy is indispensable as an essential part of comprehensive cancer treatment, particularly for subsequent therapy after surgical resection. However, small-molecule drugs for chemotherapy always cause inadequate efficacy and severe side effects against cancer metastasis and recurrence caused by lymph node metastases. Here, we developed doxorubicin-carried albumin nanocages (Dox-AlbCages) with appropriate particle sizes and pH/enzyme-responsive drug release for tumor and lymph node dual-targeted therapy by exploiting the inborn transport properties of serum albumin. Inspired by the protein-templated biomineralization and remote loading of doxorubicin into liposomes, we demonstrated the controlled synthesis of Dox-AlbCages via the aggregation or crystallization of doxorubicin and ammonium sulfate within albumin nanocages using a biomineralization strategy. Dox-AlbCages allowed efficient encapsulation of Dox in the core protected by the albumin corona shell, exhibiting favorable properties for enhanced tumor and lymph node accumulation and preferable cellular uptake for tumor-specific chemotherapy. Intriguingly, Dox-AlbCages effectively inhibited tumor growth and metastasis in orthotopic 4T1 breast tumors and prevented postsurgical tumor recurrence and lung metastasis. At the same time, Dox-AlbCages had fewer side effects than free Dox. This nanoplatform provides a facile strategy for designing tumor- and lymph node-targeted nanomedicines for suppressing cancer metastasis and recurrence.

Evaporating crystallization effect of ammonium sulfate at atmospheric pressure under the action of ultrasound

Ultrasound enhanced evaporating crystallization has been proposed to solve the problems of low crystallization yield and uneven particle size in the evaporating crystallization process of ammonium sulfate solution at atmospheric pressure. The effects of key operating parameters, including the ultrasound power, stirring speed, pH value, and ultrasound time, on the yield of ammonium sulfate product and the duration of solid–liquid transformation time are studied. The results show that the ultrasound crystallization can increase the ammonium sulfate yield by 52.9 %, reduce the solid–liquid transformation time of ammonium sulfate by 10 %, and obtain ammonium sulfate products with higher crystallinity and more uniform particle size. Ultrasound promotes the crystallization of ammonium sulfate by enhancing the transfer of heat in the solution and reducing the supersolubility of the ammonium sulfate solution from 937.5 g/L to 833.33 g/L. This study provides experimental justification for the use of ultrasound in atmospheric evaporative crystallization.

Preparation, Characterization, and Scattering Characteristics of Mixed Aerosol of Fly Ash and Ammonium Sulfate

The mixed aerosols formed by fly ash and ammonium sulfate have a vital impact on the scattering characteristics of the atmosphere. This paper proposes to investigate the scattering characteristics of an individual optically levitated mixed aerosol of fly ash and ammonium sulfate using a coupled laser levitation and scattering measuring apparatus. The mixed aerosols were first prepared and characterized by multiple techniques. The results demonstrated that mixed aerosol particles completely encapsulated ammonium sulfate crystals on the rough porous surface of fly ash, resembling the “core-shell” structure. Moreover, the surface formed columnar ammonium sulfate crystals that exhibit the highest regularity when the solid mass concentration of fly ash was 1000 mg/L. The scattering intensity of mixed aerosols was measured, and the comparisons among fly ash aerosol and mixed aerosols were made to evaluate the effect of fly ash concentration on scattering. The measurements demonstrated that the mixed aerosols exhibited a lower overall scattering intensity compared to fly ash alone. The higher regularity of ammonium sulfate crystals formed on the surface of mixed aerosols at different solid mass concentrations of fly ash corresponds to higher scattering intensity. These findings will be helpful for recognizing the scattering characteristics of real atmospheric aerosols in depth.

Study on the Mass transfer and hygroscopic behavior of glucose / ammonium sulfate aerosol droplets

Organic aerosols can form semisolid state, glassy state and high viscous state in the atmosphere, which makes aerosols show nonequilibrium kinetic characteristics following the loss of water due to the extended timescales for diffusive mixing. In this study, aerosol optical tweezers (AOTs) and confocal Raman spectroscopy are utilized to investigate the mass transfer of water and the hygroscopicity of internally mixed glucose/ammonium sulfate aerosol droplets with different organic/inorganic molar ratios (OIRs). The characteristic time ratio between the droplet radius and the RH is calculated to describe the mass transfer of water in the droplets. The results shown that the characteristic time ratio of the mixed glucose/ammonium sulfate aerosol droplets is apparently lower than that of pure glucose droplets. And the characteristic time ratio of the mixed droplets decreases with the increase of ammonium sulfate. The hygroscopicity of mixed glucose/ammonium sulfate aerosol droplets is greatly affected by high viscosity organic matter, and the glassy state of glucose suppresses the crystallization of ammonium sulfate in the system. Compared with the pure ammonium sulfate droplets, the efflorescence relative humidity (ERH) of the mixed glucose/ammonium sulfate droplets is delayed and the deliquescence relative humidity (DRH) is advanced. The ERH of the mixed aerosol droplets with molar ratios of 1:4, 1:3 and 1:2 is 35 ± 2%, 32 ± 2.5% and 30 ± 1.5% RH, respectively. And the DRH of the mixed aerosol droplets is 78 ± 1.5%, 76 ± 2% and 74 ± 2.5% RH, respectively. These results improve the understanding of the physical and chemical properties of super viscous organic/inorganic mixed aerosols, and might have important implications for atmospheric chemistry.

Effect of Evaporation Temperature and Mg2+ Concentration on the Crystallization of Ammonium Sulfate

AbstractThis study investigates the influences of the evaporation temperature and Mg2+ concentration on the crystallization of an ammonium sulfate mother liquor. Specifically, their effects on the solubility, metastable zone width, crystallization amount, average particle size, and coefficient of variation of ammonium sulfate are examined through the laser and evaporation crystallization methods. Results show that solubility increases and the metastable zone width narrows with an increase in the evaporation temperature. At an evaporation temperature of 338.15 K, the controllability of the crystallization process improves and explosive nucleation does not easily occur. In this case, crystals with large average particle sizes, regular morphologies, and high crystallinity are obtained. With an increase in the Mg2+ concentration in the solvent, solubility decreases. The added Mg2+ covers the active nucleation sites, thus hindering the nucleation of ammonium sulfate and widening the metastable zone width. At a Mg2+ concentration of 0.9 g L−1 or higher, Mg2+ covers the active surfaces of the grains. This inhibits normal crystal growth and hinders the nucleation and growth of ammonium sulfate crystals, so the crystallization amount of ammonium sulfate significantly reduces.

Influence of the Neutralization Degree on the Ice Nucleation Ability of Ammoniated Sulfate Particles

AbstractPrevious laboratory measurements suggest that ammonium sulfate crystals (AS, (NH4)2SO4) are efficient ice‐nucleating particles under cirrus conditions. Sulfate particles not completely neutralized by ammonium are less well studied and include two other solids, ammonium bisulfate (AHS, NH4HSO4) and letovicite (LET, (NH4)3H(SO4)2). In this work, we have obtained the first comprehensive data set for the heterogeneous ice nucleation ability of crystallized particles in the AS–LET–AHS system as a function of their degree of neutralization at a temperature of about 220 K. Quantitative data on nucleation onsets, ice‐active fractions, and ice nucleation active surface site densities were derived from expansion cooling experiments in a large cloud chamber and measurements with two continuous flow diffusion chambers. We found a strong dependence of the efficiency and the mode of heterogenous ice nucleation on the degree of neutralization. Ice formation for AS, mixed AS/LET, and LET crystals occurred by the deposition nucleation or pore condensation and freezing mode. The lowest nucleation onset was observed for AS, where 0.1% of the particles became ice‐active at an ice saturation ratio of 1.25. This threshold gradually increased to 1.35 for LET, and abruptly further to 1.45 for mixed LET/AHS crystals, which partially deliquesced and induced ice formation via immersion freezing. Pure AHS crystals did not form due to the inhibition of efflorescence. Our data allow for a more sophisticated treatment of ice formation in the AS–LET–AHS system in future model simulations, which have so far only considered the available data for AS alone.

Optimization of Ammonium Sulfate Crystallization under the Action of Ammonium Chloride Using the Response Surface Method

Optimization of Ammonium Sulfate Crystallization under the Action of Ammonium Chloride Using the Response Surface Method

Interfacial co-assembly strategy towards gradient mesoporous hollow sheet for molecule filtration

Gradient porous structures enable the fast capillary-directed mass transport and enhance the chemical reaction rate with optimal efficiency and minimal energy consumption. Rational design and facile synthesis of functional mesoporous materials with sheet structure and gradient mesopores still face challenges of stacked structures and unadjustable pore sizes. Herein, an interfacial co-assembly strategy for gradient mesoporous hollow silica sheets is reported. The modulated oil-water interface allows the assembly of gradient mesoporous silica layers on the water-removable ammonium sulfate crystals. The obtained mesoporous silica layers possess narrow pore size distributions (~2.2 nm and ~6.6 nm). Owing to the good mono-dispersity, sheet structure and proper pore size, the designed gradient mesoporous hollow silica sheets can serve as flexible building blocks for fabricating nanoscale molecule filtration device. Experiments reveal that the obtained nanofiltration device shows remarkable gradient rejection rates (range from 23.5 to 99.9%) for molecules with different sizes (range from 1.2 to 4.4 nm).

Process optimization and crystallization kinetics of ammonium sulfate from wet ammonia‐based desulfurization

AbstractThere are some problems in the production of ammonium sulfate, a byproduct of the ammonia desulfurization process, such as small crystal size and uneven distribution. The evaporative crystallization kinetics of ammonium sulfate and the factors affecting the crystallization of ammonium sulfate for improving the quality of ammonium sulfate were studied. The results showed that the largest mean diameter of ammonium sulfate was obtained at a stirring speed of 400 r/min, evaporation temperature of 60 °C, and pH of 5.0. The particle size of the ammonium sulfate increased when the crystal seed was introduced. The metastable region of ammonium sulfate was determined by laser method. The crystallization process of ammonium sulfate was studied using population balance equations and intermittent dynamic method, and the empirical equation of nucleation rate and growth rate of ammonium sulfate crystallization was obtained. This experiment can provide a solution for the problems existing in the production of ammonium sulfate in the process of ammonia desulfurization.

Influence of ammonium nitrate on the crystallisation of ammonium sulfate

ABSTRACT This study aims to explore the influence mechanism of ammonium nitrate produced by ozone denitrification on the crystallisation of ammonium sulfate, a by-product of ammonia desulfurisation. The laser method was used to study the influence of ammonium nitrate on the solubility and metastable zone width of ammonium sulfate. An experiment on the influence of ammonium nitrate on the particle size of ammonium sulfate was designed, and the influence mechanism was explored through scanning electron microscopy and X-ray diffraction. The findings showed that the addition of ammonium nitrate increased the size and aspect ratio of ammonium sulfate crystals. The addition of ammonium nitrate inhibited the dissolution of ammonium sulfate and widened its metastable zone. The addition of ammonium nitrate covered the active sites of crystal nucleus growth, which inhibited the formation of crystal nuclei to a certain extent, and crystal growth dominated the crystallisation process. Moreover, the addition of ammonium nitrate induced the preferred orientation of the specific crystal plane of ammonium sulfate, and the addition of a small concentration of ammonium nitrate decreased the crystallinity of ammonium sulfate. The research results can provide a reference for crystallisation optimisation and quality improvement of ammonium sulfate in the ammonia desulfurisation process.

Insight into the structural properties of methyl orange, hexamethyl pararosaniline chloride dyes doped potassium hydrogen phthalate ammonium sulfate crystals and their antibacterial applications

Insight into the structural properties of methyl orange, hexamethyl pararosaniline chloride dyes doped potassium hydrogen phthalate ammonium sulfate crystals and their antibacterial applications

Optimization of Ammonium Sulfate Crystallization Under Ammonium Nitrate Based on Response Surface Method

AbstractThe response surface method is used to study the influence mechanism of three factors (seed crystal concentration, pH value, and stirring rate) on ammonium sulfate crystallization (average particle size and coefficient of variation [C.V.] value) under ammonium nitrate to prove the effect of ammonium nitrate doping on ammonium sulfate crystallization. Regression equations between each response value and the influencing factors are established. Results show that the interaction between the seed crystal concentration and the stirring rate is stronger than that between the seed crystal concentration and the pH and that between the pH and the stirring rate. The error between the verified model values and the experimental values is minimized when the seed crystal concentration is 1.5%, the pH is 4.5, and the stirring rate is 250 r min−1, at which the average particle size is 1.238 mm, and the C.V. value is 73.53. After optimization, the crystal morphology changes from needle‐ and flake‐like crystals to cubes, resulting in crystals with large average particle size, uniform distribution, regular morphology, and diffraction peak intensity that is close to that in the analysis of pure ammonium sulfate.

Exploration of process optimization for recovery of sodium and ammonium sulfate crystals from vanadium precipitation wastewater

In this paper, we have studied vanadium precipitation wastewater in two stages of the fractional crystallization process. In order to extract sodium sulfate and ammonium sulfate products with large particle size and uniform particle size distribution from the rear end vanadium precipitation wastewater and to realize the resource reuse of vanadium precipitation wastewater, the effects of various operating parameters (seeding amount, evaporation rate, stirring rate, growing time) on the particle size and particle size distribution of sodium sulfate and ammonium sulfate products were investigated. Better separation and crystallization conditions of sodium sulfate and ammonium sulfate were obtained. The optimized crystallization conditions of sodium sulfate are: the addition amount of ammonium sulfate seeding with a particle size of 40 μm is 1.17 %, the evaporation rate is 100 mL/h, the stirring rate is 80 rpm, the crystal growth time is 60 min, and the main particle size M.S. value of sodium sulfate crystals is 242.23 μm; The optimized crystallization conditions of ammonium sulfate were as follows: the addition amount of sodium sulfate seeding with a particle size of 80 μm was 0.68 %, the evaporation rate was 160 mL/h, the stirring rate was 150 rpm, and the crystal growth time was 30 min. The M.S. value of the final ammonium sulfate crystal was 880 μm.

Recovery of nitrogen and phosphorus from livestock slurry with treatment technologies: A meta-analysis

The livestock industry has developed rapidly in recent decades, but the improper treatment of livestock manure, especially slurry, causes environmental pollution. Treatment technologies are considered to be effective in alleviating nitrogen (N) and phosphorus (P) losses from livestock slurry. Here, we used published research data to conduct a meta-analysis of the recovery efficiencies of N and P of five mainstream treatment technologies, including ammonia stripping, air scrubbing, membrane filtration, microalgae cultivation and struvite crystallization. Additionally, the agronomic effects of the recovered products of these treatment technologies were evaluated. The results showed that all technologies exhibited clear recovery effects on N and P. The N recovery efficiencies ranged from 57% to 86%, and those of P ranged from 64% to 87%. Struvite crystallization was the most efficient treatment technology for both N and P recovery; moreover, the ammonia stripping and microalgae cultivation technologies were less efficient. The pH levels and temperatures are the main factors that influence ammonia stripping, struvite crystallization and microalgae cultivation, while membrane filtration and air scrubbing are mainly affected by the membrane types and properties. When the equal amount of N or P input to fields, the recovered products (ammonium sulfate and struvite crystals) may achieve a similar crop yield, relative to commercial N or P fertilizers. Our findings can provide deep suggestions and parameters for designing proper treatment technologies to reduce nutrient discharge from livestock slurry in regions with high livestock density and also for identifying the research gaps that should be paid more attention in the future.

Exploration of Process Optimization for Recovery of Sodium and Ammonium Sulfate Crystals from Vanadium Precipitation Wastewater

Exploration of Process Optimization for Recovery of Sodium and Ammonium Sulfate Crystals from Vanadium Precipitation Wastewater

Causes and Control Technology of Slurry Overflow in an Ammonia Desulfurization Tower.

In the flue gas ammonia desulfurization process of the coal chemical industry, ammonium sulfate slurry in the desulfurization tower often foams and overflows, which wastes resources and pollutes the environment. The solution to this problem remains largely unknown. This paper aims to reveal the causes of foaming by analyzing foam composition, ammonia desulfurization process raw material source, and characteristics of the flue gas source of the coal chemical industries. It is seen that the organic carboxylate ammonium salt surfactant in the slurry was the main cause of ammonium sulfate slurry foaming. Moreover, due to ammonium sulfate crystals and ash in foam forming a skeleton to support the foaming structure, the foam was not easy to break. More importantly, an appropriate defoaming agent was screened and optimized by an ammonia desulfurization tower simulated device in the laboratory. The YLZ-3 compound defoaming agent, with the optimal defoaming efficiency, was obtained by combining a polyether siloxane copolymer, n-octyl alcohol, fumed silica, and deionized water. It had a good temperature stability and little influence on the ammonium sulfate slurry drying time. However, defoaming agent addition could affect the ammonium sulfate crystal form. The foam overflowing could be controlled by spraying the defoaming agent from the top of the tower. Thus, the problem of bubbling overflow of the ammonia desulfurization tower could be resolved very well.

Biofertilizer recovery from organic solid wastes via hydrothermal liquefaction

Hydrothermal liquefaction (HTL) has emerged as a viable pathway for processing wet organic solid wastes (OSW) to yield biocrude oil which could be upgraded to transportation fuels and specialty chemicals. The HTL process results in two byproducts laden with high levels of carbon, nitrogen, and phosphorous. Recovery of phosphates in the byproducts as struvite and ammoniacal-nitrogen (NH4-N) as ammonium sulfate is proposed here as a promising pathway to utilize the HTL byproducts. A case study of this pathway using algal biomass as a model OSW yielded 8.2 g struvite/100 g OSW and 10.7 g ammonium sulfate/100 g OSW. Heavy metal levels in both struvite and ammonium sulfate crystals were below EPA regulations for land application. This biofertilizer recovery pathway could render OSW processing by HTL a greener alternative to anaerobic digestion, offering feedstock versatility, substantially smaller footprint, and a higher degree of OSW valorization.

Features of isothermal crystallization of ammonium sulphate

Soil fertility is rapidly decreasing due to irrational land use, erosion and soil pollution and adverse weather conditions. The use of composite granular organic-mineral fertilizers that contain mineral and organic components allows the soil fertility to be increased in the most effective and safe manner for the environment. In the production of granular composite fertilizers in a fluidized bed granulator, the process of isothermal mass crystallization is the main parameter that affects the quality.
 The effect of impurities on the morphological structure of ammonium sulfate microcrystals during mass crystallization on the surface was investigated by means of microscopic analysis. The influence of temperature and pH of the solution on the structure and shape of the microcrystal layer was studied.
 The process of mass crystallization depends on the presence of impurities, pH and temperature. Given the fact that there is no analytical or theoretical dependence describing the influence of impurities on the morphological structure, the influence is determined experimentally. The presence of even a small content of surfactants and other impurities in the ammonium sulfate solution has a significant effect on the morphological structure of ammonium sulfate microcrystals, which is revealed as reduction in the concentration of impurities in ammonium sulfate obtained by coke-chemical method. The pH level of the medium affects the structure and shape of microcrystals: smaller crystals with a layered structure are formed in the case of weakly alkaline medium with pH = 8 and smaller microcrystals with a granular structure are formed in the case of pH = 4. Therefore, it is important to maintain the required pH level of the medium during the mass crystallization of ammonium sulfate.
 In isothermal mass crystallization of saturated aqueous solutions of ammonium sulfate with humic compounds and bone meal proceeding on a surface with temperature 90 °C, small elongated crystals with microcrystal sizes from 10 to 100 μm are formed. Impurities of bone meal and humic compounds in the form of inclusions are placed between the crystals of ammonium sulfate: namely, the endosegregation of impurities in the microcrystalline framework is observed. As the concentration of organic matter in the solution increases, which crystallizes as droplets on the surface, rubble and dendrites are formed outside the initial droplet placement. This phenomenon is explained by the increase of diffusion resistance at the center of the drop; as a result, ammonium sulfate crystallizes in the zone with lower resistance.
 The process of isothermal mass crystallization of saturated aqueous solutions of ammonium sulfate with admixtures of humic compounds, bone meal and other target components in the specified ratios will create new highly effective fertilizers. The obtained results allow formulating theoretical bases for the formation of solid structures based on ammonium sulfate with admixtures of organic and mineral components.

Optimization of ammonium sulfate crystals based on orthogonal design

Orthogonal experiments were performed to explore the influence of various factors and interactions on the crystal size and shape of ammonium sulfate: pH, stirring speed, and the Fe3+ addition amount of ammonium sulfate solution. The influence mechanism was analyzed by combining the characterization results of scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). The results show that Fe3+ addition has an effect on the crystallization of ammonium sulfate. pH affects the viscosity of the solution and the width of the metastable zone, potentially influencing the grain size and crystal shape as well as crystal agglomeration. The stirring speed affects the crystal nucleation rate. With increasing stirring speed, the average crystal particle size and its coefficient of variation (C.V.) both increase at first and then decrease. The resulting ammonium sulfate crystals have a broad particle size distribution. The average particle size increases with increasing C.V. value, which is tend to larger particle sizes. Optimal purity of ammonium sulfate crystals is obtained at a liquor pH of 3.4, the stirring speed of 200 r∙min−1, and Fe3+ addition amount of 0.84 g. These results can serve as a reference for related research on the optimization of the ammonium sulfate crystallization process.

Oriented Crystallization of Ammonium Sulfate from Hexagonal Boron Nitride/Sulfuric Acid Intercalation Compounds

Controlling crystallization is a long-standing issue both from a fundamental and an applied perspective. In particular, our understanding of the influence of confinement on crystallization is far from complete. In this work, we utilize the confined interlayer spaces of hexagonal boron nitride (h-BN), which is one of the typical two-dimensional layered materials with atomically flat BN sheets, not only to prepare h-BN/H2SO4 intercalation compounds but also to initiate crystallization via the acid/base reaction between the intercalant (H2SO4) and gaseous ammonia. We report that the present acid/base reaction leads to the formation of highly oriented ammonium sulfate crystals along specific crystallographic directions. This oriented crystal growth originates from the 2D crystal nucleated in the confined interlayer spaces of h-BN.